1. Field of the Invention
The present invention relates generally to surgical devices and, more particularly, to an improved surgical clip structure and method for constricting anatomical vessels and organs.
2. Description of the Prior Art
Surgical ligating clips are widely used to constrict or occlude anatomical tissue, such as tubular vessels and organs, during surgical procedures. The clips are generally U-shaped with opposed arms being positioned around anatomical tissue and clamped together in order to constrict the tissue. Instruments for applying surgical clips, commonly referred to as "clip appliers," can be configured for applying a single clip or multiple clips in series and can be adapted for use in both open and minimally invasive (i.e., endoscopic) surgical procedures.
Prior art surgical clips are commonly made of ductile metals, such as titanium, and are secured to tissue by squeezing or crimping opposed arms of the clip across the tissue after the clip has been properly positioned. Once crimped, the arms of a metal clip tend to remain crimped; however, metal clips will occasionally come off the tissue to which they have been applied when knocked by instruments moved about the operative field or, in the case of occluded vessels, the clips will loosen as a result of the vessels bulging.
Some metal clips also have a distal locking feature whereby distal ends of the opposed arms are configured to interlock; however, since central portions of the arms remain free to move, these clips will also tend to loosen over time when used to occlude vessels that bulge.
Other prior art surgical clips are made from materials that cannot maintain a deformed shape, such as certain bioabsorbable materials. These clips are secured around tissue by use of interlocking members carried on opposed arms of the clip. However, since the arms of these clips will not retain a crimped shape in the event that the interlocking members fail to engage, clips of this type will not function as desired when there is incomplete engagement of the interlocking members. Furthermore, the materials from which such clips are made can relax over time causing the clips to loosen, whereby, for example, a vessel lumen would cease to be effectively occluded.